# IL-18 Signaling and Lung Epithelial Cell Barrier Integrity in Severe Asthma

> **NIH NIH F32** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2021 · $52,121

## Abstract

PROJECT SUMMARY/ABSTRACT:
 Asthma is a common disease, affecting more than 300 million people worldwide. Though well controlled
in most, some experience disease that is refractory to standard treatments such as corticosteroids. Recent
efforts focused on understanding these severe asthma (SA) patients suggests ontological heterogeneity.
Previous work from the Severe Asthma Research Program (SARP) cohort linked epithelial gene signature to
clinical phenotype. We revisited this data set and identified 3 novel groups of asthmatics, one of which
housing the majority of SA cases and having the worst lung function and greatest exacerbation history. Using
principal drivers of variance in the data set, we found that expression of the interleukin 18 receptor (IL18R1)
along with 18 other genes was able identify at-risk asthmatics. IL18R1 has been previously linked to asthma in
genome-wide association studies. Its ligand, interleukin-18 (IL-18), may be a cofactor for both Th1 and Th2
inflammation. High IL-18 levels have been detected in serum and sputum of asthmatics including in those with
fatal asthma. Importantly, IL-18 and IL18R1 regulate epithelial barrier function in other inflammatory
conditions. We have confirmed an increase in IL18R1 at the protein level in SA patients compared to healthy
controls (HC) using lung biopsies from very severe asthma cases. These SA patients also harbor increased
numbers IL-18+ cells, the cognate ligand for IL18R1. Downstream targets of IL18 stimulation, including the
active phosphorylated forms of JNK1 and c-Jun, show increase in SA airway epithelium. SA patients also
show disorganization of adherens junctions, suggesting breakdown in epithelial barrier integrity.
 Based on this background and our preliminary data, we hypothesize that IL-18 pathway activation, via
elevated IL18R1 expression in bronchial epithelium, promotes dysregulated barrier function that contributes to
SA pathobiology by increasing immune cell access to foreign antigens. We propose 2 aims to address this:
Aim 1. We will interrogate pre-existing tissue banks for quantitative analysis of IL18R1 and compare that with
levels of its ligand in tissue and fluids from these patients. These data will be corroborated with activity of
associated signaling pathways and tight/adherens junction integrity.
Aim 2. We will us primary human airway epithelial cells, obtained bronchoscopically from HCs and asthmatic
patients to mechanistically confirm and expand upon the results from Aim 1. This will include validation of ex
vivo results as well as quantification of barrier function.
 These data will identify a novel role for IL18 in severe asthma pathogenesis and open up new avenues
for treatment of this difficult and costly disease. The activities of the project will provide the PI with valuable
experience in obtaining, culturing and manipulating primary human airway epithelial cells and lay the
foundation for future in vivo work by integrating study in computational...

## Key facts

- **NIH application ID:** 10116175
- **Project number:** 5F32HL147415-02
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Matthew Camiolo
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $52,121
- **Award type:** 5
- **Project period:** 2019-12-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10116175

## Citation

> US National Institutes of Health, RePORTER application 10116175, IL-18 Signaling and Lung Epithelial Cell Barrier Integrity in Severe Asthma (5F32HL147415-02). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/10116175. Licensed CC0.

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